Hotspots Come Unstuck

Volcanic hotspots are widely believed to be caused by fixed volcanic sources deep in the mantle. In her Perspective, Stock highlights the report by Tarduno et al., whose paleomagnetic data cast doubt on the fixity of the hotspot underlying the Hawaiian-Emperor seamounts. The data suggest that not only plate motion but also mantle flow have determined the latitudes of the islands and seamounts in the chain. With current data, it is difficult to say whether the base of the hotspot has remained fixed or whether it is a third variable determining the motion of surface volcanism with time.